Field of the Invention
This present invention is generally directed towards electronic human prosthetics, and specifically an implantable bi-directional neural-communication device where the input, output and on-board computing are combined into a single unit to form a compact neuro-prosthetics device.
Background of the Invention
Neuroplasticity is an intrinsic property of the human central nervous system (CNS) and represents the ability of actively adapting to environmental pressures, physiologic changes, and experiences. Neuroplasticity occurs either during normal brain development when people begin to process new sensory information, or as an adaptive mechanism to reform neurological paths due to brain or spinal cord injury (SCI). Damage to the CNS affects at least 2 million people per year. Compensation for brain or spinal function loss occurs after CNS injuries such as stroke or SCI. The result of this compensation may take place not only in the cortex, but also involves other subcortical parts. Thus, systems that can interpret different level of brain activity and use it to control mechanical and computer components have immense potential for applications in various fields.
Brain-computer-interfaces are systems that provide communications between human beings and machines. Brain-computer-interfaces can be used, for example, by individuals to control an external device such as a wheelchair. A major goal of brain-computer interfaces is to decode intent from the activity of an individual, and signals representing the decoded intent are then used in various ways to communicate with an external device. Brain-computer-interfaces hold particular promise for aiding people with severe motor impairments.
Electroencephalographic signals (EEG) acquired from scalp electrodes, and single neuron activity assessed by microelectrodes arrays or glass cone electrodes, are considered a safe and non-invasive modality, but have low spatial resolution, a poor signal to noise ratio due to signal attenuation by the skull, and signal contamination from muscle activity. In contrast, single-unit recordings of the signals from an individual neuron convey a significantly finer spatial resolution with higher information transfer rates and enable the use of more independent channels. However, single unit recordings require close proximity (within 100 microns) with neurons and therefore are not generally suitable for human applications because of the much higher associated clinical risk, and the lack of durable effect secondary to scar formation around the electrodes.
Devices implanted in or interfaced with the human nervous system today typically operate in open-loop mode and have yet to achieve the goals of processing neural data robustly, chronically, safely, and in a functionally meaningful way. For example, no implantable commercial pacemaker system exists today for fully closed-loop control system. Further, power supply remains an issue and rechargable batteries are not addressed within current integrated systems.